Drafting instrument.



J. SAMSUNOFF.

DRAFTING INSTRUMENT.

APPLICATION rum) IEB. 2. 1907.

91 8,599, Patented Apr. 20, 1909.

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Unrrnn STATES PATENT OFFIQE.

JOSEPH SAMSONOFF, OF NEW YORK, N. Y.

DRAFTING ms'rmnvmiv'r.

To all whom it may concern:- Be liZ-kIlOWIl that I, J osnrrr SAMSONOFF, a

subject of the Czar of Russia, residing at the 'city of New York, county and State of New'York, have invented a new and useful Improvement in Drafting Instruments, of whichthe following is a specification.

This invention relates to improvements in drafting instruments and particularly to that class of drawing instruments, which is used for obtaining aliquot parts of angles.

.On account of the fact, that the ratio of the diameter of a circle to its circumference is a mixed number, consisting in part of a whole number, and in part of a decimal fraction, it is, as is well known, practically impossible to calculate accurately more than 'afew divisions of a circle, such parts as can not be so calculated are still more difiicult to measure,;in fact we have no accurate and correctinstruments for laying off these odd divisions. As an angle is a section of a circle subtended by two of its radii and is measured-by the intercepted arc, the same difficulty is to be surmounted in dividing it. So inuch is this so, that draftsmen and desi ners often find ita long tedious job to lay 01% such divisions. And so, much valuable time and labor are expended.

The-object of my present invention is to produce such an instrument as will by proper thereof, to produce an instrument of the character aforesaid.

The curvature of the edge" is made in accordance with certain mathematical calculations and principles.

The nature of the invention will be fully understood from the following general description and the annexed drawings, and M will be subsequently pointed out in the claims' In the accompanying drawings, which are hereby made a part of this'specification, Figurc No. I. is a side view of my newly invented instrument. Fig. No. II. is an Specification of Letters Patent.

Application filed. February 2, 1907. Serial No. 355,347.

Patented April 20, 1909.

illustration showing how the instrument is used.

T. designates the straight line ruler. The edge 6 b of this ruler is graduated. These graduations may be as illustrated, or in any other desirable and available divisions. I. designates a lateral extension on said ruler, projecting from the end of the graduated edge. This projection has one curved edge 2". and one straight edge, the meeting point of the curved and graduated edges being designated as O. The straight edge is directly at right angles to the graduated edge 5 b of the ruler, and is cut with a notch at b. Each of said graduations is equal to the distance 0 I). The curved edge 2' of this extension is a Jolysecting curve and is formed by a mathe matical method and in accordance with the divisions it is to make.

I will illustrate the principle upon which my device for dividing angles into equal parts is founded. To my invention I apply the principle of a curve drawn as the geometrical locus of vertices of triangles, whose angles at the base are in a ratio 1/11. The instrument for drawing any required curves as geometrical loci of vertices of triangles whose angles at the base are in a ratio 1/2, 1/3 1/13 1/11, is not described or illustrated, but its use in connection with my invention is herein set forth.

If upon the given straight line A F, Fig. II, two permanent points 0 and A(Z)) are taken and through 0 in relation with another respective point d, one has constructed the curve 2' as the geometrical loci of vertices of triangles, whose angles at the bases upon the line A F are in a ratio 1/13, any angle E A F is geometrically divisible by 13.

Curve 2', as drawn in relation with cl, is the geometrical locus of vertices of triangles, whose angles at the base A cl are in a ratio 1/13.

Let the curve 2' intersect E A at point (Z and connect (Z with d; then triangle (Z cl A has angle (Z A d equal to 13 angle (Z (Z A (by hypothesis), therefore the measure of angle (Z d A is angle (Z A (Z or is angle E A F.

To use my invention, suppose that it be Zn, will register with the apex of the angle 'A., then the curve 2'. will intersect the line A E, at (Z. If then the point (5, fixed on my instrument by mathematical calculations, be marked on the line A E, and the points cl d be connected, the angle A 6K (Z Will be equal to 1/13 of the angle EA F. I

The point 0 is definitely located on the straight edge at the base of the curve 2' and the point]; is also fixed and alines With said straight edge and is essentially the point 7 with Which the apex of the angle to be measever confine myself strictly to the contour and the arrangement of the instrument hereinbefore described as it is evident that under the spirit of my invention I amentitled to all'such variations of contour and arrangement as do not depart therefrom.

Having now ascertained and described What my invention is, and how the same is constructed and used, What I claim, and desire to secure by Letters Patent is: v

1. A ruler comprising a graduated straight edge, a pointed extension having one straight edge and one edge in the form of a projecting curve, the contour of which is derived by mathematical calculation so as to have a: fixed relation with reference to said graduated edge and projecting laterally from one end of the latter, and a determined distance between the meeting points of the two edges of said extension With the straight edge.

2. As a new article of manufacture, an instrument'for measuring the aliquot parts of angles, comprising a ruler having a'graduated straight edge and a point extension It is also evident that with in an instrument of the class described comprising a ruler provided with a graduated straightedge, a projection having one curved and one straight edge, said straight'edge extending right angles to said graduated ed e and having a notchin alinement therewith, the curve of said curved edge being such as to locate the vertices of triangles whose base angles at two given points on the graduated edge have predetermined ratio. i

A ruler provided with a graduated straight edge, having a lateral end projection with one straight ungraduated edge and one curved edge meeting at a point, said said said said strai ht ed 'e alinin with the end of 1 a 1 c: rmer and OXtQIlCllD" at ri ht an les to 1 c a: 2,: graduated edge, the straight edge of extension having a notch at its point of meeting with the end of said ruler, the contour of said curved edge adapted. to locate the vertices of all triangles Whose base an gles at two given points of said graduations have a predetermined ratio.

in testimony Wiereof, l have signed my name to this specification in the presence of two subscribing Witnesses, this twenty-second day of January 1907.

JOSEPH SAMSONOFF.

"iVitnesse NATHAN COHEN, Isroonn M. SIEBERMAN. 

